In the course of current medical practice, an increasing number of tissue samples are presented for histological examination. The tissue samples are preserved by subjeciing them to various solutions including fixative solutions, dehydrating solutions and clearing solutions. Subsequently, the tissue sample is embedded in material, typically paraffin or another suitable embedding wax, and then sliced very thinly with a microtome for microscopic examination.
A substantial portion of a histology technician's time is frequently occupied with preparation of tissues, generally routine procedures which utilize time that might be better spent on other work. Although the processing and embedding protocols are routine, these protocols must be carefully adhered to in order to obtain an embedded tissue sample from which precise tissue sections may be prepared. Generally protocols require that the tissue sample be soaked in each processing liquid for a time sufficient for the processing liquid to fully penetrate into all portions of the tissue. Each processing liquid should be substantially completely removed before the next processing liquid is introduced.
It is a general object of the present invention to provide apparatus by which most of the steps of preparing tissue samples for examination can be effected automatically without the constant attention of the technician. It is a further object of the invention to provide apparatus which more effectively provides for complete exchange of processing and embedding fluids.